1. Field of the Invention
The invention relates to a selective calling and dialling arrangement for a mobile radio station in a radio transmission system.
2. Description of the Prior Art
A selective calling and dialling arrangement, that produces radio telegrams addressed to a specific person, is described in TE KA DE Technische Mitteilungen 1980, pages 10 to 14, more specifically pages 12 and 13. The selective calling and dialling arrangement described in the German document is shown in FIG. 1, and is provided in a radio telephony set which together with radio device FG and operating device BG forms part of the mobile radio station. The radio telegrams are transmitted via the radio device FG. This selective arrangement interprets received pulse telegrams and controls both the radio device FG and also the indicator of the control device BG. In addition, the selective calling and dialling arrangement interprets the keyboard information fed into the control device BG.
The selective calling and dialling arrangement comprises a microprocessor CPU which is connected via data, address and control busses (omnibus system) to stores (PSP, DSP RSP, KSP and SP1) to a counting circuit (T) and to an input/output arrangement (E/A). To render addressing of the stores (PSP, DSP), the counter circuit (T) and the input/output arrangement (E/A) possible, the selective calling and dialling arrangement includes an address decoder (not shown). The program for the microprocessor CPU is stored in a program store PSP which is in the form of a read-only memory. The selective calling and dialling arrangement comprises a data store DSP for storing variable data which are, for example, required during the program flow.
The calling number memory or store RSP and the identification store KSP provide the necessary data for transmitting a called party's number, based on a called party code entered via the keyboard of the control device BG, and recognizing received calls which are intended for this subscriber or station.
Those of ordinary skill in the radio telecommunications art will recognize the typical flow of signals and the major circuit or function sections. For example, the demodulator section DEM for incoming data is shown, while the corresponding modulator section for outgoing (transmitted) traffic is not shown separately.
Constants which define specific countries, for example call channel numbers, search tuning ranges and the maximum channel command, which is connected to the input/output arrangement E/A, are stored in a first store SP1 of the selective calling and dialling arrangement. By shifting country-specific constants from the program store PSP to the first store SP1, the number of programs for different countries can be kept very low.
In the standard specifications of the different operators of radio transmission systems, system constants such as, for example, the number of radio reports to be transmitted, dialling tones, indications, HF and jitter thresholds, number of repetitions or periods for supervision, are fixed and stored in the program store PSP. These system constants are set non-recurrently before the radio transmission system is made operative and can only be changed at great cost and effort during operation. The manufacturers of mobile radio stations include the predetermined system constants somewhere in each developed program, so that changing the system constants is similar to a change in the program stored in the program store PSP. In the TE KA DE Technische Mitteilungen 1980 it is disclosed to store constants which differ from country to country not in the program store PSP but in the additional store SP1.
3. Other Developments German Offenlegungsschrift No. 33 14 557, Published Oct. 25, 1984, proposes a transmission and receiver arrangement for radio telephony which comprises a store which is capable of being programmed with subscriber-specific parameters, and a microcomputer assigned to this store. This provides the user with the possibility to make a selection from sets of predetermined parameters. This makes it possible for the user to select the output characteristics he desires, also without special technical knowledge. This selection is comparable to the way described in TE KA DE Technische Mitteilungen 1980 for selecting between sets of system constants which differ from country to country. Adapting the transmission and receive arrangements when the sets of parameters are changed requires the replacement of the microcomputer itself. This replacement is necessary because of the then necessary change in the program.